This application relates generally to digital signal detection, and more particularly to a nonlinear Viterbi detector for use in an iterative decoding system.
With the continuing demand for high-speed digital communications systems and high-density digital storage systems, various techniques have been applied to increase the capacity of these systems. For example, in magnetic media storage, many manufacturers are using perpendicular recording rather than traditional longitudinal recording to pack more information into a smaller area. However, as data speeds and storage densities are pushed to their limits and beyond, the amount of signal distortion on information-carrying signals have increased dramatically. Thus, detectors are heavily relied upon to interpret the information in these highly distorted signals.
In fact, digital transmission and storage systems have reached a point where signal-dependent noise, such as transition jitter, often overwhelm signal-independent, white noise. Therefore, nonlinear Viterbi detectors, designed to whiten signal-dependent noise, are currently being used in place of their less-effective linear counterparts. However, current nonlinear Viterbi detectors are highly complex. They may also have high power consumption and large area because of high throughput requirements. In iterative decoding systems and other systems that utilize multiple nonlinear detectors, the complexity, area, and power requirements of current nonlinear Viterbi detectors may be overly costly. Therefore, it would be desirable to provide techniques for reducing the complexity, area, and/or power requirements of nonlinear Viterbi detectors for iterative decoding systems and other systems where multiple Viterbi detectors are used.